Nonequilibrium in the Translational Equations of Motion: The purpose of this study was to evaluate the extent of error in the implementation of the translational equations of motion associated with the use of a fifteen segment rigid body model of the human form to evaluate gait. Geometric models and kinematic data processing techniques are capable of producing acceptably low levels of nonequilibrium when implementing the translational equations of motion. However, efficacy of these techniques must be questioned in regards to their poor performance during the more impulsive phases of gait. Mechanical Power Generation: Muscle related power generation in human walking has been evaluated. Previous data processing techniques provided joint power terms in planes associated with anatomically based coordinate systems. Problems with this technique included: 1) the over-representation of segmental power, and 2) integration of power time histories did not conform to inertial reference frame requirements. The significance of joint power term imbalances is currently being evaluated.